1. Field of the Invention
The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting or receiving channel state information in a multiple input multiple output (MIMO) system supporting coordinated transmission.
2. Brief Description of the Background Art
Various apparatuses and techniques such as smart phones or tablet PCs requiring machine-to-machine (M2M) communication and high data transmission rate have appeared. Accordingly, the amount of data to be processed in a cellular network has rapidly increased. In order to cope with rapid increase in the amount of processed data, a carrier aggregation technique and cognitive radio technique for efficiently utilizing a larger frequency band, a MIMO technique and multiple base station coordination technique for increasing a data capacity transmitted within a restricted frequency band, etc. have been developed.
Among others, in order to improve performance of a wireless communication system, a coordinated multiple point transmission and reception (CoMP) scheme has been proposed. The CoMP scheme is expected to improve performance of a user equipment (UE) located at a cell edge and improve average sector throughput. However, even when the CoMP scheme is applied, inter-cell interference (ICI) which reduces the performance of a UE located at a cell edge still occurs, thus there is an issue for channel estimation of a UE which is provided with a communication service using the CoMP scheme.
In order to maximize efficiency of a transmission and reception scheme such as a CoMP scheme, a channel state between a base station and a user equipment (UE) should be accurately estimated. However, up to now, a method of obtaining channel state information of a wireless communication system using a CoMP scheme has not been defined.
The technical problems solved by the present invention are not limited to the above technical problems and other technical problems which are not described herein will become apparent to those skilled in the art from the following description.